Six Turkish soldiers were killed and one injured on Monday afternoon in an attack by suspected Kurdistan Workers' Party (PKK) militants in the Sirnak province, Dogan News Agency reported.The attack targeted a Turkish military checkpoint in Uludere, a district in Sirnak Province, Xinhua news agency reported.The Uludere incident came just hours after four soldiers were killed in a previous bombing attack, also blamed on PKK militants, in Mardin province.Over 600 members of Turkish security forces and thousands of PKK members have been killed in confrontations inside Turkey and in northern Iraq since July 2015, local media said.More than 40,000 people have lost their lives in clashes with the PKK since 1984, when the group first started anti-government attacks.The PKK is listed as a terrorist organisation by the United States, the European Union and Turkey.